IDM Pharma Receives Recommendation for Approval of Mifamurtide (MEPACT(R), L-MTP-PE) for the Treatment of Patients with Non-Metastatic, Resectable Osteosarcoma in Europe from the Committee for Medicinal Products for Human Use (CHMP).

IDM Pharma, Inc. (Nasdaq: IDMI) today announced that the Committee
for Medicinal Products for Human Use (CHMP) of the European Medicines
Agency (EMEA) has issued a positive opinion, recommending grant of a
centralized marketing authorization for mifamurtide (L-MTP-PE), known as
MEPACT(R) in Europe, for the treatment of patients with non-metastatic,
resectable osteosarcoma, a rare and often fatal bone tumor that
typically affects children and young adults. The CHMP recommendation
will be adopted at the next CHMP meeting in December with final European
Commission approval expected within 60 to 90 days thereafter.

Granting of the centralized marketing authorization will allow
L-MTP-PE to be marketed in the 27 Member States of the European Union
(EU), as well as in Iceland, Liechtenstein and Norway. L-MTP-PE would be
the first approved new treatment in more than 20 years for patients with
osteosarcoma. L-MTP-PE was granted orphan medicinal product status in
Europe in 2004. Therefore, under European pharmaceutical legislation,
L-MTP-PE is entitled to a period of 10 years market exclusivity in
respect of the approved indication.

"The recommendation for approval by the CHMP is a great
victory for many young patients and their families and is a significant
step for the Company in bringing this important treatment to
market," said Timothy P. Walbert, president and chief executive
officer, IDM Pharma. "The Committee's decision validates the
clinical trial data and the belief of investigators, patients and IDM
Pharma that L-MTP-PE provides a significant overall survival benefit for
osteosarcoma patients and meets a significant unmet treatment
need."

The positive opinion was based in large part on the Phase 3
L-MTP-PE trial (INT-0133), a National Cancer Institute (NCI) funded
cooperative group study conducted by the Children's Oncology Group
(COG) and the largest study completed in osteosarcoma, enrolling
approximately 800 patients. The study was designed to evaluate patient
outcomes with the addition of L-MTP-PE to three- or four-drug adjuvant
chemotherapy (cisplatin, doxorubicin, and methotrexate with or without
ifosfamide).

Overall survival after six years of follow-up in patients treated
with chemotherapy and L-MTP-PE was 78 percent, compared to 70 percent in
patients treated with chemotherapy (p=0.03) alone. The addition of
L-MTP-PE to chemotherapy resulted in approximately a 30 percent decrease
in the risk of death.

Treatment with L-MTP-PE was generally well tolerated in all phases
of clinical development. Adverse events were mild to moderate in
severity and included chills, fever, nausea, vomiting, myalgia,
headache, tachycardia (fast heart rate), hypo- and hypertension, fatigue
and shortness of breath, all of which are consistent events with the
activation of monocytes and macrophages by L-MTP-PE and the flu-like
symptoms that follow cytokine release. These side effects are readily
prevented or treated with acetaminophen.

If approved by the European Commission, it is anticipated the
Company would conduct certain post-authorization studies or analyses to
address follow up questions about L-MTP-PE.

L-MTP-PE U.S. Regulatory Status

As previously announced, in the United States the Company continues
to work with the COG as well as external experts and advisors to gather
patient follow up data from the Phase 3 clinical trial of L-MTP-PE and
to respond to other questions in the non-approvable letter the Company
received from the U.S. Food and Drug Administration (FDA). The Company
expects to submit the amended New Drug Application (NDA) in the first
quarter of 2009 given the recent focus on completing review activities
for the Marketing Authorization Application (MAA) in the European Union.

L-MTP-PE was granted orphan drug status in the United States in
2001 and the NDA was submitted to FDA in October 2006 and was accepted
for review in December 2006.

About Osteosarcoma

Between two and three percent of all childhood cancers are
osteosarcoma. Because osteosarcoma usually develops from osteoblasts, it
most commonly affects children and young adults experiencing their
adolescent growth spurt. Boys and girls have a similar incidence rate
until later in their adolescence, when boys are more commonly affected.
While most tumors occur in larger bones, such as the femur, tibia, and
humerus, and in the area of the bone that has the fastest growth rate,
they can occur in any bone. The most common symptom is pain, but
swelling and limited movement can occur as the tumor grows.

Osteosarcoma is an orphan disease with fewer than 1,000 new cases
diagnosed in the United States each year. A similar incidence of the
disease exists in Europe. According to the Children's Oncology
Group, the survival of children with osteosarcoma has remained at 60-65
percent since the mid-1980s. The standard treatment for osteosarcoma is
tumor resection with combination chemotherapy before and after surgery.

About IDM Pharma

IDM Pharma is focused on the development of innovative cancer
products that either destroy cancer cells by activating the immune
system or prevent tumor recurrence by triggering a specific adaptive
immune response. IDM Pharma is dedicated to maximizing the full
therapeutic and commercial potential of each of its innovative products
to address the needs of patients and the physicians who treat these
patients.

The Company believes it has adequate cash resources to support its
operations into the first half of 2009 based on its current development
and operating plans. The Company does not currently have operational
sales and marketing infrastructure for L-MTP-PE and does not currently
have plans or sufficient funds to secure this capability. The Company
continues to evaluate strategic alternatives, which may include seeking
strategic partners, a merger and/or the sale of all or part of its
operations and assets, or raising additional capital to secure
operational sales and marketing infrastructure for L-MTP-PE.

For more information about the company and its products, visit
http://www.idm-pharma.com.

Forward-Looking Statements

This press release includes forward-looking statements that reflect
management's current views of future events including statements
regarding the timeframe in which the Company's cash will be
sufficient to meet planned operations, the Phase 3 L-MTP-PE trial
(INT-0133), the potential for L-MTP-PE as a treatment for osteosarcoma,
the Company's belief that the data from the L-MTP-PE Phase 3 study
warrants regulatory approval of L-MTP-PE from an overall clinical
benefit/risk standpoint in Europe and the United States, the expected
timing of a final opinion from the CHMP and receipt of a final
regulatory decision regarding the MAA in the European Union, and plans
for the conduct of post-authorization studies and analyses, as well as
the Company's plans to collect, analyze and submit additional Phase
3 data in an amended NDA for L-MTP-PE, including the expected timing for
such amended NDA, and to respond to other matters raised by the FDA and
the Company's plans to evaluate strategic alternatives. Actual
results may differ materially from the forward-looking statements due to
a number of important factors, including, but not limited to, whether
the European Commission will follow the final opinion of the CHMP once
issued, whether the timing for the final opinion of the CHMP and the
regulatory decision in Europe will occur as expected by the Company, the
timing of filing an amended NDA with the FDA, the possibility that
additional data from the Phase 3 clinical trial of L-MTP-PE and other
information in any amendment to the NDA for L-MTP-PE submitted by the
Company may not provide adequate support for regulatory approval of
L-MTP-PE in the United States within the timeframe expected by the
Company, if at all, whether the Company will be able to complete any
potential strategic transaction on terms acceptable to the
Company's stockholders, how the volatile economic environment will
affect the Company's efforts to complete a strategic transaction,
and whether the cash resources of the Company will be sufficient to fund
operations as planned. These and other risks affecting the Company and
its drug development programs, intellectual property rights, personnel
and business are more fully discussed in the Company's Quarterly
Report on Form 10-Q filed with the SEC for the quarter ended September
30, 2008 and other periodic reports filed with the SEC. The Company
expressly disclaims any intent or obligation to update these
forward-looking statements, except as required by law.